1. Field of the Invention
The present invention relates to sport shoes, and more particularly, to replaceable inserts for the sole of a sport shoe.
2. Description of the Prior Art
The sport shoe has reached a high level of development in the last twenty years. The basic running shoe, including a relatively soft upper and elastomeric sole, has been fine-tuned to a great degree of specialization. A specific shoe is now available for every sport. Within the sport of running, different designs can be found, whether for jogging or running marathons. Within such specialization, a different shoe can be found for a heavy male runner or for a light female runner. A sole design can also be found for someone who requires support against over-supination or over-pronation.
Such specialization of sport shoe designs has led to a large spectrum of different shoes. For instance, if an amateur runner wishes to go for a light jog of only a few kilometers, he cannot wear his pair of running shoes designed for racing. The heel cushion in the racing shoes will have a greater durometer hardness because the shock to be absorbed will be naturally greater than what is required for a light run. In the latter case, the runner will experience some discomfort since the heel will appear to be too hard. Likewise, a softer heel portion of the heel will seem too soft for a hard competitive run.
In order to satisfy all different types of running, a person would need to own several pairs of running shoes, much like a golfer requires a set of different clubs for use with different approach shots. However, running shoes are relatively expensive, and such a solution is not practical for the average runner.
Replaceable sole inserts have been contemplated for sport shoes. Examples of such shoes are described in U.S. Pat. No. 4,624,061, issued Nov. 25, 1986 to Wezel et al; U.S. Pat. No. 4,942,677, issued Jul. 24, 1990 to Flemming et al; U.S. Pat. No. 4,897,936, issued Feb. 6, 1990 to Fuerst; and U.S. Pat. No. 5,533,280, issued Jul. 9, 1996 to Halliday.
The above patents describe various methods of replacing different inserts in the sole of a shoe. In particular, U.S. Pat. No. 4,942,677 describes the use of damping plates in the heel portion of the sole for the purposes of damping the shock absorbing characteristics of the shoe. This patent includes an outsole hinged to the remainder of the sole, and wedge-shaped damping elements are inserted between the outer sole and the upper to provide proper damping or spacing in order to enhance the height of the person wearing the shoe.
U.S. Pat. No. 4,942,677 shows a structure that is best suited for more rigid dress shoes, not modern day sport shoes. Sport shoes generally have a much softer construction. A sport shoe sole constructed with a heel and replaceable insert as found in U.S. Pat. No. 4,942,677 would tend to be plagued with lateral instability since there is no structure illustrated in the patent to resist the shear forces that might occur in a more violent side sliding movement, such as in basketball or tennis.